Field
The present disclosure relates to a vehicle control apparatus for executing a control for preventing a vehicle from colliding against an object existing in a forward direction with respect to a vehicle or preventing the vehicle from strongly colliding against the object.
Description of the related art
A collision reduction system is known (for example, see JP H09-287488 A and JP 2013-129288 A). This collision reduction system prevents an own vehicle from colliding strongly against an object such as a wall in a parking area and a preceding vehicle traveling in front of the own vehicle by limiting an engine output torque output from an internal combustion engine of the own vehicle to a torque equal to or smaller than a constant torque when a driver of the own vehicle operates an acceleration pedal in mistake for a brake pedal in the case that a traveling speed of the own vehicle is zero or extreme small (for example, equal to or smaller than 5 km/h).
A collision avoidance system is also known (for example, see JP 2013-129288 A). This collision avoidance system prevents the own vehicle from colliding against the object existing in a forward direction of the own vehicle by forcibly braking the own vehicle by a braking device to stop the own vehicle before the own vehicle collides against the object when the driver of the own vehicle drives the own vehicle at a traveling speed equal to or larger than a predetermined traveling speed without realizing the object.
The collision avoidance system is configured to detect a distance between the object and the own vehicle, a relative speed between the object and the own vehicle by using a sensor such as a millimeter-wave sensor and determine whether or not a forced braking of the own vehicle by the braking device should be performed on the basis of the detected distance and the detected relative speed. Hereinafter, the detected distance will be referred to as “the object distance”.
In this regard, when the traveling speed of the own vehicle is an extreme small traveling speed, detection accuracies of the object distance, the relative speed and the like may not be accuracies necessary for forcibly braking the vehicle, depending on a type of the sensor or a detection algorithm for detecting the object on the basis of an output of the sensor.
As a result, if a performance of the forced braking is permitted with the traveling speed of the own vehicle being the extreme small traveling speed, the own vehicle may be forcibly braked although the driver of the own vehicle intends to stop the own vehicle at a position close to the object with an operation of the acceleration pedal as an acceleration operator. Thereby, the driver may feel discomfort
Accordingly, in the collision avoidance system that the detection accuracies of the object distance, the relative speed and the like do not satisfy the accuracies necessary for forcibly braking the own vehicle, a condition that the traveling speed of the own vehicle is equal to or larger than a predetermined traveling speed is set as a condition for performing the forced braking. Hereinafter, for convenient, in some cases, the predetermined traveling speed will be referred to as “the forced braking permission vehicle speed”.
On the other hand, the collision reduction system determines whether or not a torque output from a torque output device as a vehicle driving source such as the internal combustion engine or an electric motor should be limited on the basis of the detected object distance. Hereinafter, the torque output from the torque output device will be referred to as “the output torque”. Further, the collision reduction system prevents the own vehicle from colliding strongly against the object when the object distance is small, in particular, when the driver of the own vehicle drives the own vehicle into a garage and then, stops the own vehicle or when the driver of the own vehicle stops the own vehicle in a parking area. Thus, in the collision reduction system, a condition that the traveling speed of the own vehicle is zero or the extreme small traveling speed is set as a condition for limiting the output torque to a torque equal to or smaller than a constant torque. Therefore, when the collision reduction system is activated to limit the output torque, the traveling speed of the own vehicle is smaller than the forced braking permission vehicle speed and thus, the forced braking by the collision avoidance system is not performed.
In this regard, the inventor of this application has realized that when the object distance is relatively large, if the output torque is not limited, the traveling speed of the own vehicle reaches the forced braking permission vehicle speed by the relatively large output torque and at this time, if the forced braking is performed, the own vehicle is prevented from colliding against the object. In other words, according to a conventional technique, although the own vehicle can be stopped by the forced braking before the own vehicle reaches the object, the output torque is limited by the collision reduction system and as a result, the vehicle may reaches the object.
The present disclosure has been made for solving the aforementioned problem. One object of the present disclosure is to provide a vehicle control apparatus which can reduce a possibility that the vehicle collides against the object existing in the traveling direction of the own vehicle when the driver of the own vehicle operates the acceleration pedal mistakenly when the traveling speed of the own vehicle is zero or the extreme small traveling speed.